Brief history of the Slavic tribes

Traditional Slavic dance called "Kolo" 

Once upon the time, when our mother Earth was still intact, people preferred to live in groups. Among many groups on the face of Earth, there was one group of people which will become the most numerous group of people in the Europe by the present times. Slavic people, was least documented group of "barbarians" by Roman empire. Historians argue whether they lived as nomads, or in some primitive groups, or even that they had a king and lived in a very developed "states" for that time. One of the most common thing that almost all historians agree is that their origins were somewhere in Russia. From there, they started a long journey in every direction, and so , today we have few different groups of Slavic tribes. That partition is based on which part of Europe certain Slavic tribe inhabitates now. So, we have Eastern, Western and Southern Slavs today.
Eastern Slavs are Russians, Ukrainians and Belarusians (major groups) and Rusyns (minor group).
Western Slavs are Poles, Czechs, Slovakians (major groups) and Kashubians and Sorbs (minor groups).
South Slavs are Serbs, Croats, Bosniaks, Bulgarians, Macedonians, Montenegrin and Slovenes.
In the terms of the religion, Slavs are divided into two main groups : Orthodox Christian (Eastern church) and Catholic Christian (Western church). Ortodox Slavs are (for the most part) : Russians, Ukrainians, Serbs, Bulgarians, Belarusians, Montenegrin and Macedonians. Catholic Slavs are Poles, Croats, Slovaks, Slovenes and Sorbs. There are some minorities mostly of the South Slavic people
who are Islamic. Biggest group is Bosniaks and few sub-divisions (Gorans, Pomaks and Torbesh).

Saint Basil's Cathedral in Moscow

In the history, there were many unions, but also many disunions of the Slavic tribes. Most famous unions were :Kingdom of Samo (623-658 AD), Great Moravia (833-902 AD), Balaton Principality (839-876 AD), Kievan Rus' (9th-13th c.AD), Czechoslovakia (1918-1992 AD) and Yugoslavia (1918-1992 AD). Disunions sometimes happened peacefully (split-up of Czechoslovakia) but sometimes it happened with great problems and sometimes even with war (brakdown of Yugoslavia).
One of the unions which never occured was Slavic Union. Story starts sometimes in 1848. in Prague, Czech where this meeting was held. The meeting is called The first Slavic congress and it was attended by international celebrities of the Slavic movement. The chairman of this event was František Palacký (AKA Father of the Czech nation). This meeting was the main cause of starting this Union. Many years later, in 1999, in Russia, few Russian people decided to start this story once again. The leader of the organization is Dmitry Demushkin (Дмитрий Николаевич Дёмушкин). This Slavic Union story was great thing, but it was banned all across Russia and other Slavic states for being similar to Nazi ideology and it's founders either locked-up or they fled to other countries and asked for asylum.

Nevertheless, Slavic people always sought for collectivity instead of individuality and I think there will be more unions in the future.